Speaking after the inquest in Oxford on Friday, Mr Keys said: "What the families fully intend to pursue with the utmost vigour is to bring to account the people that put these six RMPs in such a position that allowed them to be unlawfully killed."

L/ Corp Tom Keys, 20, was one of six military police officers killed by an Iraqi mob in a police station in Al Majar Al Kabir on 24 June 2003.

Recording his verdict, coroner Nicholas Gardiner said the soldiers should have been better equipped, but said their deaths could not have been avoided.

Mr Keys, from Llanuwchllyn near Bala in Gwynedd, said the soldiers' deaths had been caused "by negligence".

Tom Keys had served in Sierra Leone and Northern Ireland

Mr Keys said: "There is not a day that goes by that we don't wonder what went on in the back room of that police station."

He said he had been on a "two-and-a-half-year learning curve" to find out for himself what happened that day, as he shared the families' distrust of the Army's ability to investigate itself.

"We are now concerned that Richard (his younger son) could be deployed to Iraq, or Iran if that all explodes, and we've lost confidence in the Army and what could happen."

Weapons of mass destruction

He said he remained angry because his son had died because of the prime minister's "lies" about Saddam Hussein having weapons of mass destruction.

He said: "Tony Blair said in 2003 that Saddam Hussein could remain in power if he did not have weapons of mass destruction, but it was a pack of lies to justify an invasion.

"That's why I am angry, because my son believed his prime minister and he died because of those lies."

The former paramedic training officer, who was propelled into the national spotlight by his son's death when he stood against Tony Blair in his Sedgefield constituency at the general election, denied he was an anti-war campaigner.

He said: "People have taken me as being an anti-war activist but I am not, I was anti this particular war because I felt that all other means of handling the situation were not exhausted.

He added: "We were a military family and we accepted that soldiers sign an oath of allegiance.

"I had to countersign Tom's papers because he was under 18."

MoD spokesman Colonel Peter Davies said his "heartfelt sympathies" were with the families and friends of the six Red Caps.